Paper post-processing apparatus

ABSTRACT

A paper post-processing apparatus comprises a processing tray section; a post-processing section; a paper discharge tray section; a first chuck section configured to hold the rear end of the paper standing by in the buffer section; a second chuck section configured to hold the rear end of the paper loaded on the processing tray; and a third chuck section configured to hold the rear end of the paper loaded on the paper discharge tray; wherein a next paper is fed onto the paper held by the first chuck section in the buffer section, a paper is fed onto the paper held by the second chuck section from the buffer section in the processing tray section, and a paper is discharged onto the paper on the paper discharge tray held by the third chuck section from the processing tray section in the paper discharge tray section.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority fromJapanese Patent Application No. 2013-078176, filed Apr. 4, 2013, theentire contents of which are incorporated herein by reference.

FIELD

Embodiments described herein relate to a technology in which apost-processing of a paper discharged from an image forming apparatussuch as a copier, a printer and a compound machine is carried out.

BACKGROUND

A paper post-processing apparatus arranged at the paper discharge sideof an image forming apparatus comprises an intermediate tray (bufferingmechanism) configured to temporarily load a plurality of papersdischarged from the image forming apparatus, a processing trayconfigured below the intermediate tray to load a plurality of papersfalling from the intermediate tray, and a paper discharge trayconfigured to load the papers discharged from the processing tray.

The intermediate tray includes a pair of intermediate tray members whichmove along a horizontal direction orthogonal to a conveyance direction(longitudinal direction), and the plurality of papers temporarily loadedon the intermediate tray fall to the processing tray if the intermediatetray members move in a direction away from each other. At this time, therear end part in the longitudinal direction of the paper is hit onto theprocessing tray through the rotation of a falling auxiliary member forcarrying the rear end part in the longitudinal direction of the paper.Further, the rear end part in the longitudinal direction of the loadedpaper is held by a rear end holding section, thereby preventing that theloaded paper is pushed forward due to the friction contact with thefront end in the longitudinal direction of the next fed paper, that is,the front end in the conveyance direction when a plurality of papers isloaded on the intermediate tray in sequence.

It is preferred that the paper post-processing apparatus dischargespapers at a processing speed the same as that (the number of printingsper unit time) of the image forming apparatus. Thus, as the processingspeed of the image forming apparatus is increased, it is necessary toincrease the processing speed of the paper post-processing apparatus,meanwhile, it is also necessary to align the end parts of the dischargedpaper.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic front view illustrating a paper post-processingapparatus according to an embodiment;

FIG. 2 is an oblique view illustrating a buffer section shown in FIG. 1;

FIG. 3 is an oblique view illustrating a processing tray shown in FIG.1;

FIG. 4 is a schematic diagram illustrating a first chuck section shownin FIG. 1; and

FIG. 5 is a schematic diagram illustrating a paddle part shown in FIG.1.

DETAILED DESCRIPTION

In accordance with one embodiment, a paper post-processing apparatuscomprises a buffer section configured to hold a standby paper fed froman image forming apparatus; a processing tray section arranged below thebuffer section configured to include a processing tray to which a paperis fed from the buffer section, and be capable of conveying the paperfed from the buffer section and loaded on the processing tray towards apaper discharge direction; a post-processing section configured to carryout a post-processing on the paper loaded on the processing tray; apaper discharge tray section configured to include a paper dischargetray to which a paper bundle loaded on the processing tray and subjectedto the post-processing is discharged; a first chuck section configuredto hold the rear end of the paper standing by in the buffer section; asecond chuck section configured to hold the rear end of the paper loadedon the processing tray; and a third chuck section configured to hold therear end of the paper loaded on the paper discharge tray.

Then, the buffer section feeds a next paper onto the paper held by thefirst chuck section, the processing tray section feeds a paper from thebuffer section onto the paper held by the second chuck section, and thepaper discharge tray section discharges a paper from the processing traysection onto the paper on the paper discharge tray held by the thirdchuck section.

The paper post-processing apparatus according to the embodiment isdescribed below with reference to the accompanying drawings.

FIG. 1 is a schematic diagram illustrating the paper post-processingapparatus according to the embodiment, FIG. 2 is an oblique viewillustrating the paper buffer section shown in FIG. 1, and FIG. 3 is anoblique view illustrating the processing tray shown in FIG. 1.

A paper post-processing apparatus 1 described herein comprises a paperbuffer section 3, a processing tray section 5, a stapler section 7serving as a post-processing section which carries out a post-processingand a paper discharge tray section 9, and is arranged next to a paperdischarge side of an image forming apparatus. A processing tray 51 ofthe processing tray section 5 is arranged below the paper buffer section3, and the paper discharge tray section 9 and the stapler section 7 arerespectively arranged at the front and rear sides of the processing tray51 in a paper conveyance direction. In addition, the post-processingrefers to, for example, a sorting processing, drilling processing,folding processing, saddle stitching processing and the like carried outon a printed paper.

A paper P discharged from an image forming apparatus (not shown) iscontinuously conveyed by a paper feed roller 11 to the paper buffersection 3. As to the paper P fed by the paper feed roller 11, the frontend in the conveyance direction is referred to as the front end of thepaper, and the rear end in the conveyance direction is referred to asthe rear end of the paper. Further, the direction orthogonal to theconveyance direction is referred to as a width direction and theconveyance direction is referred to as a longitudinal direction.

The buffer section 3 holds one or a plurality of papers P on a pair ofstandby trays 31 which are arranged opposite to each other in the widthdirection, and contacts the rear ends of the papers P with a paddle 32to align the rear ends in the longitudinal direction. The standby traypairs 31 incline the front end of the paper upwards and contact the rearend of the paper P discharged to the standby tray 31 by the paper feedroller 11 with the paddle 32. When a second paper P is conveyed to thebuffer section 3, the rear end part of the first paper P loaded on thestandby tray 31 is held by the first chuck section 33. Further, thestandby tray pairs 31 carry two ends in the width direction of the paperP, and if the standby tray pairs 31 move in the width direction and thedistance therebetween is elongated, the paper P carried falls onto theprocessing tray 51 below the standby tray pairs 31.

As shown in FIG. 2, FIG. 4 (a) and FIG. 4 (b), the first chuck section33 is arranged between a pair of paddles 32 which are arranged oppositeto each other in the width direction. In the first chuck section 33, abase portion 33 a is mounted, in a rotatable manner, on a support shaft34 which extends in the width direction, and a plate-shaped chuck plate33 b extends from the base portion 33 a towards outside. The first chucksection is driven by a first chuck driving section 35 to reciprocatinglyrotate around the support shaft 34 within a given angle range. The firstchuck driving section 35 reciprocatingly rotates the base portion 33 awith an electromagnetic solenoid 35 a serving as a driving source via alink part 35 b, so as to rotationally move the chuck plate 33 b betweena position (holding position) for holding the paper P as shown in FIG. 4(b) and a position (release position) away from the holding position forreleasing the paper P as shown in FIG. 4 (a).

In the paddle 32, as shown in FIG. 5 (a), a plate-shaped first paddlepart 32 b serving as a pedestal part for carrying the rear end part ofthe paper P, a plate-shaped second paddle part 32 c made of rubbermember, a plate-shaped third paddle part 32 d made of rubber member anda plate-shaped fourth paddle part 32 e made of Mylar member are arrangedaround the base portion 32 a at a given interval in a circumferentialdirection, and seen from the rotation direction, the second paddle part32 c is behind the first paddle part 32 b, the third paddle part 32 d isbehind the second paddle part 32 c and the fourth paddle part 32 e isbehind the third paddle part 32 d. A base portion 32 a is, for example,arranged on the support shaft 34 in a rotatable manner, and isintermittently driven by a paddle driving section (not shown).

In the present embodiment, a position where the first paddle part 32 bwaits to carry the rear end part of the paper P is referred to as astandby position. When a given number of papers P are conveyed to thepaper buffer section 3, the standby tray pairs 31 move to enlarge thedistance therebetween and the papers P fall; meanwhile, the paddledriving section rotates the paddle part 32 from the standby position ina direction for one round, and stops the first paddle part 32 b again atthe standby position.

In a standby state where the paper P is held on the standby tray 31, thepaddle 32 stands by in such a manner that the first paddle part 32 b isat an inclined position substantially parallel to the standby tray 31.When the rear end part of the first paper P is aligned and carried bythe first paddle part 32 b, the first chuck section 33 rotates the chuckplate 33 b from the release position to the holding position. Theholding position of the chuck plate 33 b described herein refers to sucha position where the paper P carried on the first paddle part 32 b inthe standby state is properly clamped between the chuck plate 33 b andthe first paddle part pairs 32 b. In this way, by holding the rear endof the first paper P, it can be prevented that the first paper P ispushed forward due to the friction contact with the front end of thesecond paper P when the second paper P is discharged by the paper feedroller 11.

The first paddle part 32 b is formed by hard resin such aspolyoxymethylene (POM) resin and the like. When the rotation of thepaddle part 32 is started, the rear end part of the paper P is no longercarried by the first paddle part 32 b, and therefore falls and floats inthe air, and then the rear end part of the paper P is hit downwards bythe rotating second paddle part 32 c, and then the paper P is loaded onthe processing tray 51. The length of the second paddle part 32 c is setto a specific value such that it is long enough to hit the paper P downto the processing tray 51.

Then, the rotating third paddle part 32 d contacts with the paper Ploaded on the processing tray 51 and slides so as to contact the rearend of the paper P with the stopper section 52 arranged at the rear sidethrough friction force to align the rear ends of the papers. Therefore,the third paddle part 32 d is formed longer than the second paddle part32 c. Then the paddle part 32 continues to rotate and stops in such astate where the first paddle part 32 b reaches the standby position. Inthis state, the fourth paddle part 32 e is brought into press contactwith the upmost paper P of the papers P loaded on the processing tray51, which prevents the paper P on the processing tray 51 from beingpushed forwards by accident, and thereby preventing a poor alignment ofpapers.

The fourth paddle part 32 e made of a Mylar sheet is weak in elasticforce, and for the papers P loaded on the processing tray 51, the fourthpaddle part 32 e almost has no forward paper conveyance force againstthe fed paper P when the paper P falls from the paper buffer section 3,therefore, the papers P on the processing tray 51 won't be moved due tothe falling paper P and a good alignment is maintained.

However, if a strong forward paper conveyance force is generated againstthe paper P fed from the paper buffer section 3, there is a risk thatthe papers P on the processing tray 51 cannot be held at the aligningposition through the holding force of the fourth paddle part 32 e.

Thus, in the present embodiment, the papers P loaded on the processingtray 51 are forcibly held at the aligning position by a second chucksection 60.

The processing tray 51 holds the loaded papers P in an aligned mannerduring a period when, for example, the papers P are subjected to astapling processing by the stapler section serving as a processingmechanism for carrying out a post-processing. As shown in FIG. 3, thepapers loaded on the processing tray 51 are aligned in a horizontaldirection by a pair of horizontal alignment plates 55, 55 which arearranged opposite to each other and are capable of moving in a directionindicated by an arrow V according to the width of the paper P.

The second chuck section 60 is arranged below the paddle part 32 so asto avoid the interference with the stapler section 7. The second chucksection 60 includes a second chuck main body section 63 formed by, forexample, mounting a pressing plate 62 at the front end of an arm part61, and a second chuck driving section (not shown) for driving the armpart 61. In the second chuck main body section 63, the pressing plate 62is set to be capable of reciprocatingly moving between a pressingposition where the pressing plate 62 is brought into press contact withthe surface of the upmost paper P loaded on the processing tray 51 and aretracting position retracting upwards from the pressing position.

The second chuck section 60 holds and presses the papers on theprocessing tray 51 when the paper P is fed from the buffer section 3 tothe processing tray 51, and retracts the pressing plate 62 to theretracting position during a period from the moment the rotation of thepaddle part 32 is started to the moment the first paddle part 32 b isstopped at the standby position again, and moves the pressing plate 62to the pressing position when the first paddle part 32 b is stopped atthe standby position.

The second chuck section 60 mounts the arm part 61 on a link mechanism(not shown) or a cam mechanism (not shown) which is reciprocatinglydriven by a driving source such as an electromagnetic solenoid and thelike, and moves the pressing plate 62 upwards or downwards between theretracting position and the pressing position.

Though the number of papers loaded on the processing tray 51 isincreased and the height of the loaded papers becomes high, if thepressing plate 62 presses the papers, then the chuck section 60 stopsthe downward movement of the pressing plate 62 and can hold the paper ata certain pressing force. For example, the pressing plate 62 isenergized by a spring member (not shown) against the arm part 61, andmoves against the spring force of the spring member through the contactwith the paper. Then if the movement of the pressing plate 62 isdetected, the driving source of the second chuck section 60 is stopped.The outer periphery of the pressing plate 62 is formed in an arc shapeso as to avoid the interference with the rear end of the paper P hitdown by the second paddle part 32 c.

On the other hand, when the paper buffer section 3 holds, for example,two papers P on the standby tray pairs 31, the two papers P are fed at atime. However, as the processing speed of the image forming apparatus isincreased, it is preferred to increase the processing speed of thepost-processing apparatus 1 such that the post-processing apparatus 1carries out a paper post-processing at a speed the same as that of theimage forming apparatus. In this case, instead of waiting until, forexample, two papers P are held on the standby tray 31 of the paperbuffer section 3 and then moving the standby tray pairs 31 to let thetwo papers P fall simultaneously, the first paper P is made to stand byon the standby tray 31, and then the paper P falls by moving the standbytray pairs 31 in a state where the rear end part thereof is held by thefirst chuck section 33 before the second paper P is discharged by thepaper feed roller 11. In this case, as shown in FIG. 5 (b), the frontend of the first paper P contacts with the paper P on the processingtray 51.

Then, the second paper P is directly discharged on the first paper Pfrom the paper feed roller 11, and then the paddle part 32 is rotated.In this case, the time taken until the two papers P falls and are loadedon the processing tray 51 is shortened, thereby increasing theprocessing speed of the post-processing apparatus 1. At this time, asthe paper P or the paper bundle on the processing tray 51 is held by thesecond chuck section 60, the paper P on the processing tray 51 won'tmove towards the front end side of the paper even if the friction forcegenerated due to the conveyance force in the paper conveyance directionof the paper P fed from the paper buffer section 3 acts upon the paper Pon the processing tray 51, thereby maintaining as good alignment of thepapers.

In this case, as the standby tray 31 functions so as to hold the rearend part of the first paper P in the first chuck section 33, the standbytray pairs 31 are not needed as long as the first paper P dischargedfrom the paper feed roller 11 can be guided to the first paddle part 32b of the paddle 32 and the rear end part of the paper P can be held bythe first chuck section 33.

The rear ends of the paper P loaded on the processing tray abut thestopper section 52 and are aligned in the longitudinal direction, and ifa certain number of papers P are loaded on the processing tray 51, thestapler section 7 moves along the width direction and carries out thestapling processing at a given position. When the stapling processing isended, the stopper section 52 moves forward to move the paper bundleonto the processing tray 51.

As shown in FIG. 3, a conveyance belt 53 for conveying the paper to thepaper discharge tray section 9 is arranged at the center part in thewidth direction of the processing tray 51. A paper feed claw 54 isarranged in the conveyance belt 53 to hook and convey the paper bundleon the processing tray 51 to the paper discharge tray section 9.Similarly, the loaded paper needs no stapling processing is alsoconveyed to the paper discharge tray section 9 by the paper feed claw54.

In the paper discharge tray section 9, a plurality of paper dischargetrays 91 is obliquely arranged on the tray support section 92 in such amanner that each paper discharge tray 91 can be moved upwards ordownwards against the tray support section 92 by a paper discharge traydriving section (not shown). A paper discharge roller 93 is arranged atthe conveyance end of the processing tray 51 to discharge the paper Pconveyed from the processing tray 51 to the selected paper dischargetray 91.

A small gap is formed between the rear end of the paper discharge tray91 and a paper abutting aligning plate 94 which is arranged on the traysupport section 92 and is capable of sliding upwards or downwards, andthe rear ends of the papers or the paper bundles loaded on the paperdischarge tray 91 contact with the paper abutting aligning plate 94 andare aligned in the longitudinal direction.

As the paper discharge tray 91 is obliquely arranged in such a mannerthat the front end thereof is inclined upwards, the discharged paper Por the paper bundle slides down along the inclined surface, and the rearend thereof contacts with the paper abutting aligning plate 94 arrangedon the tray support section 92 at a position more rear than the inclineddown end of the paper discharge tray 91, thereby carrying out analigning processing in the longitudinal direction.

In a case of continuously discharging the paper P or the paper bundle tothe paper discharge tray 91, the paper P or the paper bundle moved bythe paper discharge roller 93 along the paper discharge directioncontacts with the surface of the paper P or the paper bundle which isalready discharged and loaded on the paper discharge tray 91, the paperor the paper bundle on the paper discharge tray 91 is pushed forward andthe alignment in the longitudinal direction is disorganized.Particularly, as the paper bundle is heavier than a case of dischargingtwo or three papers at a time, the paper on the paper discharge tray 91will be pushed forward more easily in a case of discharging a paperbundle.

In the present embodiment, the paper P loaded on the paper dischargetray 91 is held by the third chuck section 70, thereby preventing thepaper P or the paper bundle loaded on the paper discharge tray 91 frombeing pushed forward by the conveyance force of the discharged paper.

In addition, the first chuck section 33, the second chuck section 60 andthe third chuck section 70 are arranged more rear than the minimum papersize length L in the paper conveyance direction.

The third chuck section 70 has a paper abutting section 71 arrangedbelow the paper discharge position in an up-and-down direction based onthe paper discharge roller 93. The paper abutting section 71 protrudesmore forward than the paper abutting aligning plate 94.

The paper abutting section 71 is formed in such a manner that a paperabutting surface 73 thereof which is parallel to the paper dischargetray 91 faces to the paper discharge tray 91. Further, the paperabutting aligning plate 94 is arranged in a specific range so that thepaper abutting aligning plate 94 can contact with the rear end of thepaper or paper bundle loaded between the paper abutting surface 73 ofthe paper abutting section 71 and the paper discharge tray 91, forexample, the paper abutting aligning plate 94 can be used as a gate forclosing a paper discharge port 95 through which the paper is dischargedby the paper discharge roller 93 positioned above the paper abuttingsection 71. In the present embodiment, the paper abutting aligning plate94 moves downwards to open the paper discharge port 95 when the paper isdischarged from the paper discharge port 95, and moves upwards to closethe paper discharge port 95 when the paper discharge operation is ended.A cutout part (not shown) is formed on the paper abutting aligning plate94 at the part corresponding to the paper abutting section 71, so as notto interfere with the paper abutting section 71 when the paper abuttingaligning plate 94 moves upwards.

In a state of loading the papers P, the paper discharge tray 91 movesupwards until the surface of the loaded paper P contacts with the paperabutting surface 73 of the paper abutting section 71, so as to hold thepaper P in a manner of clamping the paper P between the paper dischargetray 91 and the paper abutting surface 73. When a paper P or a paperbundle is discharged from the paper discharge roller 93, the paperdischarge tray 91 moves downwards to form a gap between the paperdischarge tray 91 and the paper abutting surface 73 so that thedischarged paper or the paper bundle can enter the gap, and then movesupwards to hold the loaded paper.

In the present embodiment, the outer peripheral surface 72 of the paperabutting section 71 is formed as an inclined surface, therefore, thefalling paper or paper bundle discharged from the paper discharge roller93 can be loaded on the paper discharge tray 91 smoothly without anyinterference even if the rear end thereof contacts with the paperabutting section 71.

In addition, the component constituting the paper abutting surface 73may be energized by a spring member against the paper abutting section71, and a spring force of the spring member is applied to the paperthereby holding the paper. In this case, the upward movement of thepaper discharge tray 91 can be stopped through detection on the movementof the component constituting the paper abutting surface.

In this way, the paper post-processing apparatus 1 described hereinholds the paper P standing by on the buffer section 3 by the first chucksection 33, which prevents the paper P loaded on the buffer section 3from being pushed forward by a next fed paper, thereby feeding the paperto the processing tray 51 of the processing tray section 5 in a goodalignment in the longitudinal direction. At this time, as the rear endsof the papers or the paper bundles loaded on the processing tray 51 aremaintained in a good alignment and held by the second chuck section 60,the paper or the paper bundle loaded on the processing tray 51 can beprevented from being pushed forward due to the contact with the paperfed from the buffer section 3.

Further, when the paper or the paper bundle loaded on the processingtray 51 is discharged to the paper discharge tray section 9, the paperor the paper bundle loaded on the paper discharge tray 91, which is heldby the third chuck section 70, is therefore prevented from being pushedforward due to the contact with the paper or paper bundle discharged andconveyed by the paper discharge roller 93.

Thus, the paper or the paper bundle discharged and loaded on the paperdischarge tray 91 is maintained in a good alignment in the longitudinaldirection at the buffer section 3, the processing tray section 5 and thepaper discharge tray section 9, respectively, therefore the paperfinally discharged to the paper discharge tray 91 is loaded andmaintained in a good alignment in the longitudinal direction andhorizontal direction. In addition, the paper post-processing apparatusaccording to the present embodiment is described as an apparatusindependent from the image forming apparatus; however, the presentinvention is not limited to this, the paper post-processing apparatusmay also be integrated with the image forming apparatus.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the invention. Indeed, the novel embodiments described hereinmay be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the embodimentsdescribed herein may be made without departing from the spirit of theinvention. The accompanying claims and their equivalents are intended tocover such forms or modifications as would fall within the scope andspirit of the invention.

What is claimed is:
 1. A paper post-processing apparatus, comprising: abuffer section configured to hold a standby paper fed from an imageforming apparatus; a processing tray section arranged below the buffersection and configured to include a processing tray to which a paper isfed from the buffer section, and be capable of conveying the paper fedfrom the buffer section and loaded on the processing tray towards apaper discharge direction; a post-processing section configured to carryout a post-processing on the paper loaded on the processing tray; apaper discharge tray section configured to include a paper dischargetray to which a paper bundle loaded on the processing tray and subjectedto the post-processing is discharged; a first chuck section configuredto hold the rear end of the paper standing by in the buffer section; asecond chuck section configured to hold the rear end of the paper loadedon the processing tray; and a third chuck section configured to hold therear end of the paper loaded on the paper discharge tray; wherein a nextpaper is fed onto the paper held by the first chuck section in thebuffer section, a paper is fed onto the paper held by the second chucksection from the buffer section in the processing tray section, and apaper is discharged onto the paper on the paper discharge tray held bythe third chuck section from the processing tray section in the paperdischarge tray section.
 2. The paper post-processing apparatus accordingto claim 1, wherein the buffer section feeds a plurality of papersloaded on the standby tray to the processing tray by letting the papersfall.
 3. The paper post-processing apparatus according to claim 1,wherein the buffer section feeds a next paper, in a state of contactingthe front end of the paper held by the first chuck section with thepaper on the processing tray, onto the paper held by the first chucksection.
 4. The paper post-processing apparatus according to claim 1,wherein the second chuck section has a structure in which the paper ispressed from above.
 5. The paper post-processing apparatus according toclaim 1, wherein the third chuck section has a paper abutting sectionwhich abuts the surface of the rear end of the paper loaded on the paperdischarge tray so as to hold the paper through an upward movement of apaper discharge tray which is capable of moving in the verticaldirection.
 6. The paper post-processing apparatus according to claim 2,wherein the second chuck section has a structure in which the paper ispressed from above.
 7. The paper post-processing apparatus according toclaim 3, wherein the second chuck section has a structure in which thepaper is pressed from above.
 8. The paper post-processing apparatusaccording to claim 2, wherein the third chuck section has a paperabutting section which abuts the surface of the rear end of the paperloaded on the paper discharge tray so as to hold the paper through anupward movement of a paper discharge tray which is capable of moving inthe vertical direction.
 9. The paper post-processing apparatus accordingto claim 3, wherein the third chuck section has a paper abutting sectionwhich abuts the surface of the rear end of the paper loaded on the paperdischarge tray so as to hold the paper through an upward movement of apaper discharge tray which is capable of moving in the verticaldirection.
 10. The paper post-processing apparatus according to claim 4,wherein the third chuck section has a paper abutting section which abutsthe surface of the rear end of the paper loaded on the paper dischargetray so as to hold the paper through an upward movement of a paperdischarge tray which is capable of moving in the vertical direction.